The present disclosure relates to automotive vehicle access steps, including a dual action deployable access step for pickup trucks and sport utility vehicles.
In the use of automotive vehicles, and particularly those with high ground clearance such as pickup trucks and sport utility vehicles, it is often desired to gain access to elevated areas such as the cargo bed or roof rack. Various configurations of fixed and retractable steps exist which offer a number of different methods to gain access to these areas of the vehicle. However, in all cases these steps are limited by either a compromised fixed location or limited motion envelope dictated by the employed linkage or package constraints.
It would therefore be desirable to provide a deployable vehicle access step that combines both rotary and linear motions so as to afford a large and flexible deployment envelope. It would be a further enhancement if the linear and rotary mechanisms were interlocked so as to allow only selective single degree of freedom motion. Finally, a highly adaptable and efficient access step would result if an energy storage device is incorporated that imparts a torque on the rotary mechanism biasing the step towards the retracted state while also applying a force on the linear mechanism that biases the step towards a deployed state when commanded by the user.
Accordingly, the present disclosure provides a dual motion vehicle access step that can be deployed by initially rotating it around a pivot joint in response to an operator pushing down on the step to overcome a closing torque and then translating it away from the vehicle in response to a biasing force. Both of the closing torque and biasing force are provided by a single energy storage device. The combination of the rotary downward motion and linear outward motion results in the step being capable of a deployment envelope far larger than any results in the step being capable of a deployment envelope far larger than any of the existing prior art configurations.
The dual motion vehicle access step of the present invention includes a step component, a body component and a mounting bracket adapted to be rigidly attached to a vehicle. The step component incorporates a step suitable for providing a safe and convenient means of accessing elevated areas of the vehicle. The body component is configured with a rotary joint at its inboard end that is anchored to the mounting bracket allowing a single rotary degree of freedom of the body component relative to the mounting bracket. The body component further incorporates a linear motion control element adapted to constrain the step component movement to a single degree of freedom translation relative to the body component while being capable of transferring the operational step loads between the components. The body component additionally includes an interlocking latch assembly that is configured to selectively limit operation of the deployable vehicle access step to either the linear translation of the step component relative to the body component or the rotary motion of the body component relative to the mounting bracket.
The dual motion vehicle access step of the present invention includes a step component, a body component and a mounting bracket adapted to be rigidly attached to a vehicle. The step component incorporates a step suitable for providing a safe and convenient means of accessing elevated areas of the vehicle. The body component is configured with a rotary joint at its inboard end that is anchored to the mounting bracket allowing a single rotary degree of freedom of the body component relative to the mounting bracket. The body component further incorporates a linear motion control element adapted to constrain the step component movement to a single degree of freedom translation relative to the body component while being capable of transferring the operational step loads between the components. The body component additionally includes an interlocking latch assembly that is configured to selectively limit operation of the deployable vehicle access step to either the linear translation of the step component relative to the body component or the rotary motion of the body component relative to the mounting bracket.
In a further aspect of the present disclosure the dual motion vehicle access step incorporates an energy storage device adapted to impart both a torque to bias the body component into a retracted state and a force to bias the step component into a deployed state. In this manner when an operator pushes downwards on the retracted step the body component rotates to an intermediate deployed state against the biasing torque of the energy storage device and causes the interlocking latch assembly to lock the rotary joint and release the step component so that the force produced by the energy storage device then biases the step component to translate to a fully deployed position. Additionally, when an operator pushes inwardly on the fully deployed step component it translates to its retracted state against the biasing force of the energy storage device and causes the interlocking latch assembly to lock the step component and release the body component so that the torque produced by the energy storage device then biases the step component to rotate to a fully retracted state.
In a preferred embodiment of the present disclosure the interlocking latch consists of a body component ratchet, a step component ratchet, a switching pawl and a biasing plunger configured to retain the switching pawl in one of two latching states. Additionally, the body component is configured with a body component striker adapted to interact with the body component ratchet to create a structural lock and the step component is configured with a step component striker adapted to interact with the step component ratchet to create a structural lock. The switching pawl selectively retains either the step component ratchet in a locked position or the body component ratchet in a locked condition via the biasing plunger, dependent on operator input. When the vehicle access step is fully retracted the energy storage device imparts a biasing torque on the body component holding it in this state and the interlocking latch is arranged so that the switching pawl prescribes that the step component ratchet and step component striker are structurally locked and the body component striker is fully released from the body component ratchet. In this manner when an operator pushes downwards on the retracted step the body component is free to rotate to an intermediate deployed state against the biasing torque of the energy storage device but the step component cannot translate as it is structurally locked to the body component. When the vehicle access step reaches the intermediate deployed state the body component striker contacts the body component ratchet and rotates it causing the switching pawl to overcome the biasing plunger force and change states from retaining the step component ratchet to retaining the body component ratchet. The step component ratchet is therefore released and the force produced by the energy storage device biases the step component to translate to a fully deployed position. Additionally, when an operator pushes inwardly on the fully deployed step component it is free to translate to its retracted state against the biasing force of the energy storage device but the body component cannot rotate as it is structurally locked to the mounting bracket. When the step component reaches its retracted state the step component striker contacts the step component ratchet and rotates it causing the switching pawl to overcome the biasing plunger force and change states from retaining the body component ratchet to retaining the step component ratchet. The body component ratchet is therefore released and the torque produced by the energy storage device then biases the step component to rotate to a fully retracted state.
In a further preferred embodiment of the dual motion vehicle access step of the present disclosure a load link is provided which is pivotally attached to the mounting bracket and integrates the body component striker and a rotary attachment point adapted to retain the inboard end of a linear energy storage device. Additionally a motion control link is configured to pivotally attach to the load link at one end and the body component at the other. The mechanism created by the motion control link and load link allows the force generated by the linear energy storage device to be imparted as a torque on the body component and provides a varying and advantageous leverage ratio for the energy storage device so that the closing assist torque remains relatively constant through the body component's entire range of rotary motion. Additionally the mechanism is configured so as to provide a fixed rotation point for the inboard end of the energy storage device when the body component striker is structurally locked by the body component ratchet.
In an alternative embodiment of the present disclosure the interlocking latch incorporates a pair of torsion springs with their wound axis coaxially aligned with the pivot joints of the ratchets so as to bias the ratchets into an unlocked state.
In a preferred embodiment of the present disclosure the energy storage device is a gas spring.
In an alternative embodiment of the present disclosure the energy storage device is a coil spring, elastomeric spring or similar means.
Further aspects of the disclosure will become apparent from the following description.